Industrial automation uses many control devices. One useful control device combines a plurality of electrical actuated solenoids that control through valves the direction of hydraulic or pneumatic flow for actuating other downstream devices. In recent times these valves have been controlled by field busses which are often mounted adjacent the valve manifold.
Efforts have been made to modularize the field bus with modular input-output modules (I/O) so additional I/O components can be more easily added on or replaced. Each input/output module has a plurality of fittings which can all be used as input fittings, output fittings, or a mix of input and output fittings. This modularity is desirable to remotely place certain I/O modules closer to a particular sensor or machine. In the past, when such remote mounting is achieved, different remote components must be used.
Grounding of the electrical bus system is desired. Past grounding systems often relied on the fact that the housings of the modular components were often made from metallic materials which conduct electricity. The ground circuit often incorporated the metal housings as part of the ground circuit. However, this type of grounding system limited the use of housings made from electrically conductive materials. Light weight but structurally sound materials such as plastic or fiberglass are desired to replace the metal material but may not have the needed electrical conductivity required.
What is needed is a modular electrical bus system with I/O modules having a housing made from lighter weight non-metallic materials which has a grounding system incorporated therethrough.